The present invention relates to a monitoring system for an internal combustion engine and, particularly, to a monitoring system including an internal combustion engine monitor for informing an operator when to perform engine maintenance.
There are many types of internal combustion engines. Some internal combustion engines use a battery and transformer for creating a sparking signal for combusting the fuel. Other internal combustion engines have a magnet that interacts with an ignition coil for generating an ignition signal that is used for the combustion event. For the second type of engine, the ignition signal is conditioned and provided to an engine spark generating circuit for generating the spark of the combustion event. The ignition signal (see e.g., FIG. 2) typically has leading and trailing quarter-cycles of one polarity and a center half-cycle of the opposite polarity. Additionally, the center half-cycle is much larger in amplitude then the leading and trailing quarter-cycles, and typically only the center half-cycle is for combusting the fuel.
In addition, some prior art internal combustion engines include monitoring systems for informing an operator to perform engine maintenance (e.g., change oil). The monitoring system may be in the form of a module attached to the engine. Known prior art monitoring systems use a second power source (e.g., a battery, a solar power cell, etc.) for generating the power to monitor the engine. However, providing a battery or a similar power source increases costs and space requirements for the module.
Accordingly, the invention provides a monitoring system for monitoring an internal combustion engine. The monitoring system includes a power source having a winding, and a magnet that magnetically interacts with the winding, to generate a winding signal. The winding preferably includes an ignition coil.
The monitoring system further includes a conditioner that conditions the winding signal to generate a conditioned signal, a counter circuit powered by the conditioned signal that outputs an indication signal when engine maintenance is recommended, and a visual or audible indicator that provides an indication to the user upon receiving the indication signal. The indication signal may inform the operator to change the engine oil, change the engine air-filter, or other engine maintenance activity. Alternatively, the indication signal may inform the operator the number of hours the engine has ran or the number of revolutions a flywheel of the engine has completed.
The invention is an improvement over the prior art because the counter circuit is powered by the conditioned winding signal. Thus, unlike prior art engines, the invention does not require a secondary power source such as a battery or solar cell. By not requiring a secondary power source, the invention saves space and reduces costs. In addition, if the winding signal is the engine ignition signal, then the invention can utilize the unused portion of the ignition signal for powering the monitoring system (e.g., the positive quarter-cycles). Therefore, the invention better utilizes the existing components of the engine. Moreover, because the counter circuit is powered by the conditioned winding signal, the counter circuit functions only when the engine is running. That is, when the engine is not running, then the counter circuit does not receive the conditioned winding signal and, consequently, the counter circuit does not count. This is an improvement over the prior art because prior art monitoring circuits include a secondary power source that may count when the engine is not running. For example, in some prior art monitoring systems, if a key for the engine is left in an xe2x80x9conxe2x80x9d position, then the counter circuit would increase its count even if the engine is not running. However, for the monitoring system of the invention, because the system is powered by the conditioned winding signal, the monitoring system will only count when the engine is running.
Preferably, the visual indicator includes a light-emitting diode; the conditioner includes a rectifying circuit; and the counter circuit includes a microcontroller or processor, and software for operating the microcontroller. The software operates the microcontroller to count the amount of time the microcontroller receives the conditioned signal and to provide the indication signal to the indicator when the microcontroller counts a predetermined time period. Alternatively, the counter circuit includes a timer that counts the amount of time the timer receives the conditioned winding signal and provides the indication signal to the indicator when the timer counts a predetermined time period.
The monitoring system may further include a second visual or audible indicator that provides a second output in response to a second indication signal. Additionally, the monitoring system may further include a sensing circuit comprising a sensor and a third indicator connected in circuit. The sensing circuit is connected to the conditioner and is capable of sensing an engine condition (e.g., a low oil pressure condition, a high-engine temperature condition, or even a low oil condition). The third indicator provides an indication to the operator that maintenance is recommended when the sensor senses the condition.
The invention further provides a module capable of being electrically connected to an internal combustion engine. The module may be retrofitted onto existing engines. The module includes a conditioner that conditions the winding signal to generate a conditioned signal, a counter circuit powered by the conditioned signal that outputs an indication signal when engine maintenance is recommended, and a visual or audible indicator that provides indication to the user upon receiving the indication signal. The module is preferably a stand-alone module.